add component 'output_buffer'

[hansu]

This adds a component that behaves like a tristate buffer, but the outputs will be zero instead of high-Z.

I haven't found a better name. Could also be named 'output_switch' or 'multiple_output_buffer' ...

                            ┌───────────┐
  output-buffer.N.in-0 ─────┤  ──[>]──  ├───── output-buffer.N.out-0
                            │   ┌─┘     │
  output-buffer.N.in-1 ─────┤  ─┼[>]──  ├───── output-buffer.N.out-1
                            │   ├─┘     │
  output-buffer.N.in-2 ─────┤  ─┼[>]──  ├───── output-buffer.N.out-2
                            │   ├─┘     │
                   ... ─────┤   :       ├───── ...
                            │   :       │
  output-buffer.N.in-M ─────┤  ─┼[>]──  ├───── output-buffer.N.out-M
                            │   ├─┘     │
                enable ─────┤  ─┘       │
                            └───────────┘

[zz912]

Maybe "Enable binary signals" en-bin-sig

[andypugh]

The same can be achieved with mux_generic in bit mode, with a little more flexibility in "disabled" value.
This is simpler and easier to wire, though. Possibly also lighter-weight in terms of executed code.
What do you see as the use-case?

[hansu]

The same can be achieved with mux_generic in bit mode

Not really - at least not with one.

Alternatively I could use an and2 for each channel. But this would bloat my hal file unnecessarily...
I thought this component could be also useful for someone.

My use case is the following: I have an operating panel with illuminated keys. I simply want to turn off the illumination when the machine is not enabled. Otherwise the keys should get their appropriate illumination.

[andypugh]

The same can be achieved with mux_generic in bit mode

Not really - at least not with one.

Indeed, you would need one for each channel.

Is it worth considering a second set of "off" inputs (that default to zero)?

[hansu]

Is it worth considering a second set of "off" inputs (that default to zero)?

I thought about that too, but couldn't really imagine a case where this would be useful.
But yes I can add it - this makes it more flexible.

[BsAtHome]

Shouldn't you be able to set what level "off" actually is? I can imagine that someone would need negative logic.

[hansu]

Added a parameter to set the "off-level". Could also be a pin...

Regarding the name: the correct name would be something like "buffer with enable". But shortenings like 'enable_buffer' or 'buffer_enable' sound weird.

[andypugh]

It probably makes sense to not create new parameters at the moment, as they are (probably) being phased out.

[hansu]

Ok, changed to pin.